Preparation time: 10 minutes
Baking time: 20-25 minutes
 

1. Heat the oven to 180° C (350° F).
2. Cut the butter and chocolate into pieces and melt them together in the microwave or double boiler. Stir until smooth and cool to lukewarm.
3. Beat the eggs and sugar and add this mixture to the chocolate and butter. Fold in the flour until thoroughly combined.
4. Pour into a 20 cm (8") round parchment-lined cake pan and bake for 20-25 minutes.  The cake should form a light crust on top but still be slightly jiggly in the center. Test for doneness by inserting the tip of a knife: if it comes out with just a thin layer of batter, the cake is cooked.
5. Remove the cake from the oven, unmold quickly and let cool.
6. For a festive touch, dust with icing sugar.